1. Field of the Invention
The present invention is a swim fin equipped with extendable blades which are locked closed for normal use of the swim fin and moved into a locked open position in order for the diver to use his feet to fight off an attacking shark or other underwater predatory creature. More specifically, the swim fin has blades which lock closed in positions where the blades lie in a parallel arrangement with a bottom surface of the swim fin and which lock open in positions where the blades extend downward at various angles from the bottom surface of the swim fin.
2. The Prior Art
A preliminary search was conducted on the invention disclosed herein, and the following listed patents were uncovered in the search:
______________________________________ Patent No. Inventor Issue Date ______________________________________ 844,625 W. L. Spencer Feb. 19, 1907 2,016,249 W. M. Bashlin Oct. 1, 1935 2,362,518 R. L. Woodbury Nov. 14, 1944 2,665,478 A. Clemens Jan. 12, 1954 2,835,426 R. A. Terry May 20, 1958 3,581,326 R. R. Hayes June 1, 1971 4,555,848 C. J. Schultz Dec. 3, 1985 4,623,037 W. J. Kincaid Nov. 18, 1986 5,033,142 L. W. Templeton July 23, 1991 5,058,278 T. C. Colvin Oct. 22, 1991 ______________________________________
A diver who swims in the ocean may be attacked by sharks or other predatory creatures. When such an attack occurs, the diver will generally try to ward off the attack using his feet. The feet are less vulnerable to injury than the hands because of the rubber fins which cover the diver's feet. Also, the muscle groups located in the diver's legs are normally stronger than those in the diver's arms and are better able to mount a vigorous or sustained underwater defense. Finally, the legs are the body's appendages which are located furthest away from the diver's head and chest, the areas most vital to sustaining the diver's life.
Prior art swim fins are constructed of smooth rubber or other similar material so they will glide through the water with a minimum of resistance and will not injure the diver's ankles and legs. In the event of an attack by an underwater predator, prior art swim fins provide only a protective covering for the feet and do not provide the diver with any other defensive capabilities against the predator.
Diving tools, such as U.S. Pat. Nos. 3,581,326 and 5,033,142, do provide a diver with offensive capabilities against a predator. However, these tools are designed to be used in the diver's unprotected hand. Use of one of these hand-held diving tools utilizes weaker muscles than those found in the diver's legs, and requires the diver to allow the predator to move close to the diver's head and chest areas in order for the diver to strike a blow to the predator.
The present invention overcomes the problems associated with a diver using prior art swim fins and hand-held diving tools to defend himself from a predator's attack. The present invention is a swim fin with knives safely locked in closed positions within a recessed section of the swim fin. The knives can be rapidly extended by the diver into a locked open position where the knives point in a downward direction from the bottom surface of the swim fin, thus providing the diver with enhanced defensive capabilities against an attacking predator.